fazd heartwater power point module final sept 2011
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TRANSCRIPT
Heartwater: Risk to US Livestock and Wildlife
Christopher Hensley and Pete D. TeelSenior Forensic and Investigative Sciences & Psychology Double Major, 2012
And Professor and Associate Department HeadDepartment of Entomology
Texas A&M University
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Overview
• General Information• Issue & Threat• Cattle Egret• Geographic Distribution• Impact• Conclusions
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Heartwater: General Information
• African tick borne diseaseAffects ruminants (broad range of species)Not in US, but in Caribbean
• PathogenEhrlichia ruminantium
(Formerly Cowdria)
• Tick VectorsGenus Amblyomma
(12 species recognized)
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Genus Amblyomma
• A. variegatum• Tropical Bont Tick• Spread to 14 Caribbean Islands
Other principle African vector species not in Western Hemisphere• A. hebraeum• A. gemma
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Issue & Threat
• Risk of Heartwater to North America• Presence of primary vector and pathogen in Caribbean
• Discovery of native tick to be efficient experimental vector
• Role of cattle egrets as host and transport of
immature ticks
• Supportive climate
• Diversity of livestock andWildlife hosts in US
Potential Native Tick Vector
• The Gulf Coast tick, Amblyomma maculatum• Laboratory studies using a goat – tick model• Findings show A. maculatum very capable of
acquiring E. ruminantium from sub-clinical, infected goats. (See Mahan et al. 2000)
• Summation: A substantial risk as vector.• Vector capacity under field conditions not yet
tested.
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Cattle Egret: Host & Transport
• Caribbean introductions1940-50’s• Now widespread in Western
Hemisphere• Nest throughout Caribbean• Host to immature Amblyomma ticks
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Cattle Egret: Migratory Risk
• Migrate across Americas• Involved in inter-island travel• Caribbean birds found in Florida Keys
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Geographic Distribution
• Heartwater and Amblyomma vectors are widespread in Africa south of the Sahara
• Caribbean introduction and spread– First reported 1830s (limited to 3 islands)– Tick expansion 1970s-1980s to 14 islands
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Geographic Distribution
• Potential spread – North and South American mainlands
• Southeastern US at high risk– Close proximity– Suitable climate– Livestock density– Native and Exotic deer
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Impact
• Highly fatal• Economic risks
– high cost for containment and elimination• No drugs or vaccines• Surveillance testing• Quarantine
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Conclusions
•Vigilance to changes in Caribbean•Support efforts to Caribbean containment•Active surveillance of ticks from Texas to Florida and Georgia into National Tick Surveillance Program (USDA, APHIS, VS)•Contingency response at state & federal levels •Educate owners and veterinary professionals
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Resources Available
http://www.anapsid.org/heartwater.html http://www.avianweb.com/cattleegrets.html http://www.cfsph.iastate.edu/DiseaseInfo/disease.php?name=heartwater http://www.cfsph.iastate.edu/DiseaseInfo/factsheets.php http://www.epi.ufl.edu/?q=node/34 http://www.uniprot.org/taxonomy/34610 http://www.vetmed.ucdavis.edu/vetext/INF-DA/INF-DA_HEARTWATER.HTML